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Biomedical subjects

C G Silva

Publications and source records attributed to C G Silva.

9 recordsLinked to original sources
PubMed2000

Inhibition of energy production in vitro by glutaric acid in cerebral cortex of young rats.

The present study investigated the effects of glutaric acid (GA), which predominantly accumulates in glutaric acidemia type I (GA-I), on some in vitro parameters of energy metabolism in cerebral cortex of rats. We first evaluated CO2 production from [U-14C] acetate, as well as ATP levels in brain of young Wistar rats. The effect of the acid on the activities of the respiratory chain complexes were also investigated. GA was tested at final concentrations ranging from 0.5 to 5.0 mM. GA significantly reduced brain CO2 production by 50% at the concentrations of 0.5 to 3.0 mM, ATP levels by 25% at the concentration of 3.0 mM, succinate:cytochrome C oxireductase (complex II plus CoQ plus complex III) by 25% at 5 mM concentration, and NADH:cytochrome C oxireductase (complex I plus CoQ plus complex Ill) by 25% at 2.5 and 5 mM concentrations. The results strongly indicate that GA impairs brain energy production. If these effects also occur in humans, it is possible that they may contribute to the neuropathology of patients affected by GA-I.

Acetates↗
PubMed2000

[Pachycrepoideus vindemiae (Hymenoptera: Pteromalidae) as parasite of Ophyra aenescens (Diptera: Muscidae) in Brazil].

The first occurrence of the parasitoid Pachycrepoideus vindemiae on pupae of Ophyra aenescens, a fly of medical-sanitary importance, is reported. A swine carcass was used as bait to collect the insects. In the study, 302 pupae of Ophyra aenescens (Wiedemann) (Diptera: Muscidae) were obtained, 6 (1.98%) of them yielded the parasitoid Pachycrepoideus vindemiae (Hymenoptera: Pteromalidae

Animals↗
PubMed1999

Alanine prevents the decrease of Na+,K+-ATPase activity in experimental phenylketonuria.

Our objective was to investigate the effect of alanine administration on Na+,K+-ATPase activity in cerebral cortex of rats subjected to chemically-induced phenylketonuria. Wistar rats were treated from the 6th to the 28th day of life with subcutaneous injections of either 2.6 micromol alanine or 5.2 micromol phenylalanine plus 2.6 micromol alpha-methylphenylalanine per g body weight or phenylalanine plus alpha-methylphenylalanine plus alanine in the same doses or equivalent volumes of 0.15 M saline. The animals were killed on the 29th or 60th day of life. Synaptic plasma membrane from cerebral cortex was prepared for Na+,K+-ATPase activity determination. The results showed that alanine injection prevents the decrease of Na+,K+-ATPase activity in animals subjected to experimental phenylketonuria. Therefore, in case the same effects are achieved with ingested alanine, it is possible that alanine supplementation may be an important dietary adjuvant for phenylketonuric patients.

Alanine↗
PubMed1998

Inhibition of Na+,K+-ATPase from rat brain cortex by propionic acid.

Buffered propionic acid was injected s.c. into rats twice a day at 8 h intervals from the 6 to 21 days of age. Control rats received saline in the same volumes. The animals were weighed and killed by decapitation at 23 days. Whole brain and cerebral cortex were weighed and synaptic plasma membranes were prepared from cortex for the determination of Na+,K+-ATPase and Mg2+-ATPase activities. Body, whole brain and cortical weights were similar in the two groups, suggesting that propionic acid does not cause malnutrition in rats. Na+,K+-ATPase activity was significantly reduced by 30% in membranes from the propionate-treated group, whereas Mg2+-ATPase activity was not. In another set of experiments, synaptic plasma membranes were prepared from cerebral cortex of 23-day-old rats and incubated with propionic acid at final concentrations ranging from 0.1 to 2.0 mM. Na+,K+-ATPase activity, but not Mg2+-ATPase activity, was inhibited by 22-32%. Since propionic acid concentrations in plasma of chronically treated rats and of propionic acidemic children are of the same order of magnitude as those tested in vitro, the results suggest that the inhibition of Na+,K+-ATPase activity may be related to the neurological dysfunction of patients affected by propionic acidaemia.

Animals↗
PubMed1989

[Medical leave in hospital personnel].

We investigated medical leaves of personnel at Temuco's hospital from 1986 to 1987. 57% of persons had at least one leave and 54% of these had 2 or more leaves. Women and paramedicals had more medical leaves. Most absences occurred in june, july, august (p less than 0.01). Most leaves were caused by respiratory diseases (26%) with absence periods from 1 to 6 days. Infectious and parasitic diseases caused absences ranging from 1 to 42 days. Better health policies may help decrease this rather high absenteeism due to disease.

Adult↗
PubMed1989

[Prevalence of handicapped individuals in a rural community].

A specially designed questionnaire was used to detect handicapped individuals in a rural community. The type and magnitude of incapacity was evaluated by a physician. Overall prevalence was 4.2% with a peak incidence in the 45 to 64 year age group (111.1 per 1000). Leading causes of incapacity were bone and muscle disorders and nervous or sensory problems. Chronic back pain was the leading individual problem. 66.7% of handicapped individuals require assistance for their everyday life activities and 47.2% are unable to engage in any productive job.

Adolescent↗
PubMed1986

Cassette electroencephalography in the evaluation of neonatal seizures.

Three-channel cassette electroencephalographic (EEG) recording for up to 24 hours was obtained from 37 neonates with clinically diagnosed or suspected seizures but no seizure activity on routine EEG. EEG seizures were recorded in seven patients, five of whom had experienced clinical seizures in the 24 hours prior to cassette EEG recording. EEG seizures were detected in only one of nine neonates with recurring clinical episodes believed unlikely to be seizures and in only one of 18 without recent clinical events. Cassette EEG can enhance the detection and differentiation of seizures in neonates with persistent clinical episodes but is of low yield otherwise.

Apnea↗